In the cardiac systems used to date, the 3-D cardiac acquisition always takes place using an individual C-arm plane and employing software known as DynaCT-Cardiac.
Here, the C-arm is rotated in four rotation runs (two forward and two backward runs) by 200° in each case around the patient. The need for an acquisition of an angular area of 200° results from the geometrical properties of a fan emitter. This makes it necessary, for clean reconstruction, to record over 200° (180°+fan angle) instead of 180°.
During this rotational movement data is in each case acquired. By means of an ingenious selection of the starting points of the individual rotation runs, depending on the cardiac phase and cardiac frequency of the patient, the recordings can be controlled in such a way that a reconstruction of the heart at a particular cardiac phase can be generated from the totality of the data. This takes place through the existence of matching recordings from all angles necessary for reconstruction, that is complete coverage of the recording area. Through the use of four rotation runs a corridor of ±0.125 cardiac phases around the desired reconstruction cardiac phase can be achieved. In the case of secondary reconstructions at other cardiac phases impaired image quality may result, as the error of the corridor can increase to ±0.25 cardiac phases.
Because of the need for four rotation runs for clean coverage of all areas, a further disadvantage arises in the case of the previously cited method through additional overhead. The C-arm plane must be accelerated four times, braked once again and especially also re-started at the switching points, triggered on the basis of a specific cardiac phase. Massive delays can thereby occur, which in turn calls for a longer injection of contrast medium.
Even in the case of biplane systems in 3-D-Cardiac, which already boast two independent planes, only one C-arm plane (plane A) is employed in this acquisition. The second C-arm plane is moved from the acquisition area into a parking position and thus not currently used for 3-D data capture.
From US 2008/0187092 A1 a method for 2-D-imaging, in particular ECG-triggered fluoroscopy, is known, in which to determine a multiplicity of ECG-triggered recording moments for imaging, the following steps are executed in respect of a heart to be mapped: Recording of a multiplicity of images of the heart at previously prescribed temporal intervals; assignment of the images to specific cardiac phase moments; comparison of the images to determine similarity measures, which represent similar image-related states of the heart to be imaged, between two images in each case; identification of a group of images with mutual similarity measures in a prescribed area, between the pairs of images; and definition of the cardiac phase moments belonging to the images in the group as the multiplicity of ECG-triggered recording moments. In a further aspect, the method can additionally contain the step for execution of moving imaging on the basis of recordings at the specific recording moments based on an ECG-triggering.
US 2004/0097806 A1 describes an image-guided catheter navigation system, in which an icon, which represents a catheter, is superimposed on the image in the current catheter position.
DE 10 2006 056 687 A1 relates to a method for the recording and representation of electro anatomical images of the heart, in which a multi-electrode catheter is introduced for the simultaneous recording of multiple intracardial electrocardiograms in the area of the heart which is of interest. During the recording of the intracardial electrocardiograms a 3-D-image data record of the heart is recorded with a tomography-capable imaging device. This electrical and anatomical information from the heart is then overlaid.